1. Field of the Invention
The present invention relates to communication systems. More specifically, the present invention is directed to a bus communication system between a central station and a plurality of remote substations.
2. Description of the Prior Art
A known communication or dialogue system uses a two-wire line as a bus between a central station and a plurality of substations, wherein within the central station as well as within the substations transmitting and receiving devices are connected in parallel between both wires. In the known system, two voltage sources of different polarity are used in order to transmit data in both directions, whereat the transmitting and receiving circuits, respectively, are decoupled from each other by mean of accordingly biased diodes. The information transfer is made by modulating the currents flowing in both directions. The present invention improves this system in such a way that by simple means a data transfer is possible between the stations and that a current supply of the substations and a control of final control elements within the substations is possible.